Method and device for determining concealed regions in the vehicle environment of a vehicle

ABSTRACT

A driver assistance system (1) for a vehicle includes environment sensors (2), which sense a vehicle environment of the vehicle, and a data processing unit (4), which evaluates sensor data of the environment sensors (2) to detect obstacles (H) in the vehicle environment. In accordance with detected obstacles (H), concealed regions (VB) in the vehicle environment of the vehicle are determined, which concealed regions are concealed by the obstacles (H) and restrict a field of view (FOV) of optical environment sensors (2) of the driver assistance system (1).

FIELD OF THE INVENTION

The invention relates to a method and a device for determining concealedregions in the vehicle environment of a vehicle, and in particular adriver assistance system, in which concealed regions which restrict thefield of view of optical environment sensors of the driver assistancesystem are determined.

BACKGROUND INFORMATION

Vehicles increasingly comprise driver assistance systems which supportthe driver of the vehicle during the performance of driving maneuvers.Such driver assistance systems have display units which opticallydisplay the vehicle environment of a vehicle to the driver. The vehiclecameras, which generate camera images of the vehicle environment,transfer said images or image data to a data processing unit, whichprojects the image data onto a predefined projection surface, in orderto display them to the driver on a display. In addition to vehiclecameras or optical sensor units, driver assistance systems also haveadditional environment sensors, for example ultrasonic sensors.

In conventional driver assistance systems, if obstacles occur in thevehicle environment, for example if other vehicles are parked in thevicinity of the vehicle, this can result in disturbing image distortionsof the displayed image of the vehicle environment. These imagedistortions are produced by concealed regions which restrict a field ofview of optical environment sensors of the driver assistance system.

SUMMARY OF THE INVENTION

It is therefore an object of an embodiment of the present invention toprovide a method and a device for determining such concealed regions inthe vehicle environment of a vehicle.

This object can be achieved according to an embodiment of the inventionby a device having the inventive features set forth herein.

Accordingly, the invention creates a driver assistance system for avehicle, comprising

environment sensors, which sense a vehicle environment of the vehicle,and

a data processing unit, which evaluates sensor data of the environmentsensors in order to detect obstacles in the vehicle environment of thevehicle,

wherein, in accordance with detected obstacles, concealed regions in thevehicle environment of the vehicle are determined, which concealedregions are concealed by the obstacles and restrict a field of view ofoptical environment sensors of the driver assistance system.

The concealed regions produced by the detected obstacles are, in thiscase, preferably determined in accordance with a relative location ofthe relevant obstacle with respect to an optical environment sensor ofthe driver assistance system and/or in accordance with the extent orsize of the relevant obstacle.

In one possible embodiment of the driver assistance system according tothe invention, the data processing unit processes image sensor datawhich originate from optical environment sensors, in particular vehiclecameras, in the determined concealed regions.

In one possible embodiment of the driver assistance system according tothe invention, the determined concealed regions are processed by thedata processing unit in that the image sensor data are filtered by afilter.

In another possible embodiment of the driver assistance system accordingto the invention, the data processing unit covers the concealed regionsproduced by the detected obstacles with textured surfaces.

In another possible embodiment of the driver assistance system accordingto the invention, the data processing unit additionally calculates theconcealed regions produced by the detected obstacles dependent on aprojection surface used for representing the images, in particulardependent on a static two-dimensional ground surface or dependent on athree-dimensional bowl-shaped projection surface.

In another possible embodiment of the driver assistance system accordingto the invention, a control circuit is provided, which, dependent on theconcealed regions produced by the detected obstacles, controls opticalenvironment sensors, in particular vehicle cameras of the driverassistance system.

In one possible embodiment of the driver assistance system according tothe invention, the control circuit switches, in this case, dependent onthe determined concealed regions, between different optical environmentsensors of the driver assistance system.

In another possible embodiment of the driver assistance system accordingto the invention, the optical environment sensors comprise vehiclecameras, in particular fisheye cameras, which each have a predefinedfield of vision.

In another possible embodiment of the driver assistance system accordingto the invention, the data processing unit calculates the concealedregions produced by the detected obstacles in accordance with the fieldsof vision of the relevant optical environment sensors.

In another possible embodiment of the driver assistance system accordingto the invention, the data processing unit calculates the concealedregions produced by the detected obstacles in accordance with a relativespeed between the detected obstacles and the vehicle.

The invention further provides a method for determining concealedregions having the inventive features set forth herein.

Accordingly, the invention creates a method for determining concealedregions in the vehicle environment of a vehicle comprising the steps of:

evaluating sensor data, which are generated by environment sensors ofthe vehicle, in order to detect obstacles in the vehicle environment ofthe vehicle, and

calculating, in accordance with the detected obstacles, concealedregions which are concealed by the obstacles and restrict a field ofview of the optical environment sensors of the vehicle.

In one possible embodiment of the method according to the invention, theimage data sensor originating from optical environment sensors areprocessed, in particular filtered.

In another possible embodiment of the method according to the invention,the concealed regions produced by the detected obstacles are coveredwith textured surfaces.

In another possible embodiment of the method according to the invention,the concealed regions produced by the detected obstacles are calculateddependent on a two-dimensional or three-dimensional projection surfaceused for representing the images.

In another possible embodiment of the method according to the invention,optical environment sensors, in particular vehicle cameras, arecontrolled dependent on the determined concealed regions.

In another possible embodiment of the method according to the invention,the system switches between different optical environment sensors, inparticular vehicle cameras, dependent on the determined concealedregions.

In another possible embodiment of the method according to the invention,the concealed regions produced by the detected obstacles are calculateddependent on the predefined fields of vision of the relevant opticalenvironment sensors.

In another possible embodiment of the method according to the invention,the concealed regions produced by the detected obstacles are calculateddependent on a relative speed between the detected obstacles and thevehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Possible embodiments of the driver assistance system according to theinvention and of the method according to the invention for determiningconcealed regions are explained in greater detail below, with referenceto the appended figures, wherein:

FIG. 1 shows a schematic representation of an embodiment example of thedriver assistance system according to the invention;

FIG. 2 shows a block wiring diagram in order to represent one embodimentof the driver assistance system according to the invention;

FIG. 3 shows a schematic representation in order to explain the mode ofoperation of the driver assistance system according to the invention;

FIG. 4 shows a flow chart in order to represent one embodiment exampleof a method according to the invention for determining concealed regionsin the vehicle environment of a vehicle;

FIG. 5 shows another flow chart in order to represent another embodimentexample of the method according to the invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

FIG. 1 schematically shows a vehicle F, which has a driver assistancesystem according to the invention. In the represented embodimentexample, optical environment sensors are mounted on different sides ofthe bodywork of the vehicle F, which optical environment sensors sensethe vehicle environment of the vehicle F. The optical environmentsensors can be, for example, vehicle cameras which supply vehicle imagesof the vehicle environment. In the embodiment example represented inFIG. 1, the driver assistance system 1 of the vehicle F has four vehiclecameras 2-1, 2-2, 2-3, 2-4. In this case, the first vehicle camera 2-1is mounted on the front of the bodywork of the vehicle F and has a fieldof vision or field of view FOV1, as represented in FIG. 1. Furthermore,a vehicle camera is located on each of the left and right sides of thevehicle bodywork of the vehicle F, said vehicle cameras opticallydetecting the lateral vehicle environment of the vehicle F. The vehiclecamera 2-2 mounted on the left side of the vehicle F has a field ofvision or field of view FOV2. The right vehicle camera 2-3 detects thepart of the vehicle environment situated on the right of the vehicle Fand has a field of view FOV3, as represented in FIG. 1. Furthermore, avehicle camera 2-4 having a field of view FOV4 is provided on the backor rear side of the vehicle F. The four optical environment sensors 2-1to 2-4 can, in one possible embodiment, be fisheye cameras having arelatively wide field of view FOV of more than 170°. As can be seen inFIG. 1, the fields of view FOV or fields of vision of the differentvehicle cameras 2-i of the driver assistance system 1 can overlap oneanother. The different vehicle cameras 2-i are connected by means ofsignal lines 3-1, 3-2, 3-3, 3-4, for example by means of a signal linebus or vehicle bus, to a data processing unit (DVE) 4 of the driverassistance system 1. Sensor data, in particular camera images, aretransmitted to the data processing unit 4 by means of the signal lines3-i. The data processing unit 4 evaluates the sensor data of theenvironment sensors, in particular of the optical environment sensors orvehicle cameras 2-i represented in FIG. 1, in order to detect obstaclesH in the vehicle environment of the vehicle F. To this end, the dataprocessing unit 4 has a processor which carries out the data evaluationof the sensor data. The sensor data are preferably processed in realtime. In addition to the optical environment sensors 2-i, the driverassistance system 1 can also have additional environment sensors, forexample ultrasonic sensors. These additional environment sensorslikewise supply sensor data which can be evaluated by the dataprocessing unit 4, in order to detect obstacles H in the vehicleenvironment of the vehicle F. In the case of the example represented inFIG. 1, two obstacles H1, H2, for example a wall and a building, arelocated in the vehicle environment of the vehicle F. In the case of theexample represented in FIG. 1, the obstacle H1 is located in the fieldof view FOV1 of the front vehicle camera 2-1. The second obstacle H2 islocated partially in the field of view of the front vehicle camera 2-1and partially in the field of view of the left vehicle camera 2-2. Theobstacles H1, H2 in the vehicle environment are detected based on thesensor data obtained. These sensor data can, on the one hand, originatefrom the vehicle cameras 2-i represented in FIG. 1 and/or fromadditional environment sensors of the driver assistance system 1. Inthis case, the size or extent of the respective obstacle H-i isdetermined. In accordance with the size or contour, concealed regions VBwhich are, in each case, concealed by the obstacles H and which restrictthe field of view of an optical environment sensor, for example of avehicle camera 2-i of the driver assistance system 1, are calculated bythe data processing unit 4. In the case of the example represented inFIG. 1, the light beam which lies in contact with the extreme contourpoint P1 of the obstacle H1 defines the concealed region VB1 whichrestricts the field of view FOV1 of the front vehicle camera 2-1. In thesame way the light beam, which passes the extreme contour point P2 ofthe obstacle H2 defines the concealed region VB2. This second concealedregion VB2 is, on the one hand, delimited by the beam through the pointP2 and, on the other hand, by the outer line of the field of vision FOV1of the front vehicle camera 2-1. Furthermore, an additional concealedregion VB3 is produced by the obstacle H2, which concealed regionrestricts the field of view FOV2 of the left vehicle camera 2-2.

The data processing unit 4 of the driver assistance system 1 processes,in one possible embodiment, image sensor data or camera images whichoriginate from optical environment sensors 2-i, in the determinedconcealed regions VB. In one possible embodiment, the image sensor dataor camera images in the determined concealed regions VB are filtered. Inanother possible embodiment, the concealed regions VB produced by thedetected obstacles H are covered with textured surfaces or textures.

The driver assistance system 1 has a display or a display panel on whichthe vehicle environment of the vehicle F can be displayed to the driverof the vehicle F. To this end, camera images are projected onto atwo-dimensional ground surface or onto a three-dimensional bowl-shapedprojection surface. In one possible embodiment, the data processing unit4 calculates the concealed regions VB produced by the detected obstaclesH dependent on this projection surface used for representing the images.

FIG. 2 shows a block wiring diagram in order to represent one embodimentof the driver assistance system 1 according to the invention. The dataprocessing unit (DVE) 4 evaluates the sensor data which it obtains fromenvironment sensors, in order to detect obstacles in the vehicleenvironment of the vehicle F. In this case, the environment sensorsinclude, in addition to the optical environment sensors 2-i, in onepossible embodiment, additional environment sensors, with which sensordata are evaluated by the data processing unit 4 in order to detectobstacles H in the vehicle environment of the vehicle F. In the case ofthe block wiring diagram represented in FIG. 2, an additionalenvironment sensor 5 is represented by way of example, which suppliessensor data in order to detect obstacles H in the vehicle environment ofthe vehicle F. Furthermore, the driver assistance system 1 has, in theembodiment example represented in FIG. 2, a control circuit (SE) 6which, in accordance with the determined concealed regions VB, controlsoptical environment sensors, in particular the vehicle cameras 2-1 to2-4 represented in FIG. 2. In one possible embodiment, the control unit6 switches between the image data flows generated by the vehicle cameras2-i in accordance with the determined concealed regions VB. In thiscase, the image sensor data or camera images, which comprise as fewconcealed regions VB as possible or concealed regions VB having as smallan area as possible, are preferably switched through to the dataprocessing unit 4. In the case of the example represented in FIG. 1, thefront right region is normally graphically sensed by the front camera2-1 and the corresponding image data are transferred to the dataprocessing unit 4. On detecting the obstacle H1 and the resultingconcealed region VB1, the control unit 6 of the driver assistance system1 can switch over to the image data of the right vehicle camera 2-3, asthe obstacle H1 does not produce a concealed region VB within the fieldof view FOV3 of the right vehicle camera 2-3. Therefore, in the scenariorepresented in FIG. 1, the right vehicle camera 2-3 suppliesbetter-quality image data than the front vehicle camera 2-1, in thefield of vision FOV1 of which the obstacle H1 is located and produces aconcealed region VB1 there. In one possible embodiment, the dataprocessing unit 4 considers, during the calculation of the concealedregions VB, the predefined fields of vision FOV of the relevant opticalenvironment sensors or vehicle cameras 2-i. The fields of vision orviewing angles of the vehicle cameras 2-i are, in one possibleembodiment, stored in a configuration memory, to which a processor ofthe data processing unit 4 has access, in order to calculate theconcealed regions VB in accordance with the selected fields of vision.

FIG. 3 shows another traffic scenario in order to explain the mode ofoperation of the driver assistance system 1 according to the invention.In the traffic situation represented in FIG. 3, a vehicle F is moving ata speed V_(F) on a road, wherein another vehicle, which constitutes anobstacle H1, is coming towards the vehicle F on the road. Located nextto the road on the right is an obstacle H2, for example within the fieldof vision FOV of the front vehicle camera 2 of the vehicle F. Aconcealed region VB2 is produced by the obstacle H2 within the field ofvision FOV of the vehicle camera 2, wherein the concealed region VB2changes in accordance with the driving speed V_(F) of the vehicle F. Incontrast to the fixed obstacle H2, for example a building, the otherobstacle H1, namely the oncoming vehicle, is itself moving relative tothe vehicle F. The vehicle H1 obscures a concealed region VB1 within thefield of vision FOV of the front vehicle camera 2, wherein the concealedregion VB1 is dependent on the relative speed between the vehicle F andthe vehicle H1. In one possible embodiment, the data processing unit 4of the driver assistance system 1 calculates the concealed regions VB1,VB2 produced by the detected obstacles H1, H2 in accordance with therelative speed between the detected obstacles and the vehicle F. In thecase of a fixed obstacle such as, for example, the obstacle H2, therelative speed taken as the basis in this case is the ego speed V_(F) ofthe vehicle F. In the case of a mobile obstacle H1, for example anoncoming vehicle, the relative speed between the two vehicles is firstlydetermined on the basis of the sensor data, and subsequently theconcealed region VB is calculated in accordance with the determinedrelative speed by the data processing unit 4. In one possibleembodiment, the data processing unit 4 calculates the area of therespective concealed region VB2 approximately. If, for example, the twoarea contour points P1A, P1B of the oncoming obstacle H1 are set widepart, the area of the region VB1 concealed by said obstacle isconsiderably larger than in the case of a small distance between the twocontour points P1A, P1B. If the oncoming vehicle H1 is, for example, atruck, the region VB1 concealed by said truck is, consequently,substantially larger than in the case of an oncoming car. The larger thearea of the concealed region VB within the field of vision FOV of therelevant camera 2 is, the greater the adverse effect on the imagequality of the vehicle images supplied by the corresponding vehiclecamera is. In one possible embodiment, the control unit 6 of the driverassistance system 1 also considers, by means of switching or weightingthe different camera image flows which are supplied by differentcameras, the size or the proportion of the concealed regions VB presentin the field of vision FOV of the relevant camera. If, for example, theproportion of the total of the concealed regions VB (VB1+VB2) in thecamera images of the first front vehicle camera 2-1 is virtually 50%, asrepresented in the traffic scenario according to FIG. 3, the systemswitches, as of a certain threshold inasmuch as this is possible, tocamera images which are supplied by other vehicle cameras of the vehicleF.

FIG. 4 shows a flow chart in order to represent one embodiment exampleof the method according to the invention for determining concealedregions VB in the vehicle environment of a vehicle F.

In a first step S1, sensor data, which are generated by environmentsensors of the vehicle F, are evaluated in order to detect obstacles Hin the vehicle environment of the vehicle F. This is effected, forexample, by a processor or microprocessor of the data processing unit 4of a driver assistance system 1.

In a second step S2, concealed regions VB or concealed areas arecalculated in accordance with the detected obstacles H. These concealedregions VB are produced by obstacles H in the vehicle environment andrestrict a field of vision FOV of optical environment sensors of thedriver assistance system 1.

FIG. 5 shows another embodiment example of the method according to theinvention. In one possible embodiment, following the determination ofthe concealed regions VB, the image sensor data which originate from theoptical environment sensors, in which image sensor data the determinedconcealed regions VB are located, are processed by the data processingunit 4 or another unit. In this case, the image sensor data of therelevant optical environment sensors or vehicle cameras, in the field ofvision or field of view of which the concealed regions VB are located,can be filtered. Alternatively, the determined concealed regions withinthe camera images can be covered with textured surfaces.

In another possible embodiment, in step S3, the optical environmentsensors are controlled, for example the system switches betweendifferent environment sensors, in accordance with the concealed regionsVB determined or calculated in step S2. In this case, the size of thedetermined concealed regions VB or the proportion thereof of the entirefield of vision FOV of the vehicle camera can also be considered.

In one possible embodiment, in step S2, a concealed region VB producedby a detected obstacle H is calculated in accordance with thepre-configured field of vision FOV of the relevant optical environmentsensor 2-i. Furthermore, in step S3, the concealed regions VB canadditionally be calculated in accordance with a relative speed betweenthe detected obstacle H and the vehicle F.

The driver assistance system 1 according to the invention can be usedfor any vehicles, in particular road vehicles.

In one possible embodiment, the concealed regions VB determined by themethod according to the invention are evaluated for additional functionsof the driver assistance system 1. For example, in the case of onepossible application, a traffic density on a public thoroughfare can bededuced from the proportion of the concealed regions VB of the fields ofvision FOV of the vehicle camera 2-i. If, for example, a vehicle F ismoving in the middle lane on a three-lane highway, large proportions ofthe fields of vision FOV of the vehicle cameras 2 are masked by othervehicles which are driving in the same direction on the highway, if thetraffic density is high. The higher the traffic density on the road is,the greater the probability of traffic congestion arising is, inparticular if a traffic bottleneck occurs as a result of a vehicleaccident on the road. The proportion of the concealed areas VB withinthe field of vision FOV of a camera 2 consequently constitutes a measureof the current traffic density on the relevant road. This measure oftraffic density can, in one possible embodiment, be evaluated foradditional functions of the driver assistance system 1.

The invention claimed is:
 1. A driver assistance system for a vehicle,comprising: environment sensors including optical environment sensors,configured to sense a vehicle environment of the vehicle; and a dataprocessing unit, configured to evaluate sensor data of the environmentsensors in order to detect obstacles in the vehicle environment; whereinthe data processing unit is further configured to determine, from thesensor data, concealed regions in the vehicle environment dependent onthe detected obstacles, which concealed regions are concealed from arespective view of at least a respective one of the optical environmentsensors by the detected obstacles and restrict a respective field ofview of the respective optical environment sensor, wherein thedetermining of the concealed regions comprises respectively determining,from the sensor data, at least one of a size, an extent and a contour ofeach respective one of the detected obstacles, and then calculating eachrespective one of the concealed regions from the respective determinedsize, extent and/or contour of the respective detected obstacle thatconceals the respective concealed region.
 2. The driver assistancesystem according to claim 1, wherein the data processing unit isconfigured to process, in particular to filter, the sensor data whichoriginate from the optical environment sensors in the determinedconcealed regions.
 3. The driver assistance system according to claim 1,wherein the data processing unit is configured to cover the concealedregions with textured areas in the sensor data for being displayed to adriver of the vehicle.
 4. The driver assistance system according toclaim 1, wherein the data processing unit is configured to calculate theconcealed regions dependent on a projection surface used forrepresenting images by projecting the sensor data onto the projectionsurface.
 5. The driver assistance system according to claim 1, whereinthe optical environment sensors are mounted on the vehicle, and furthercomprising a control circuit configured to actuate the opticalenvironment sensors, in particular to switch between different ones ofthe optical environment sensors mounted on the vehicle, dependent on theconcealed regions.
 6. The driver assistance system according to claim 1,wherein the optical environment sensors comprise vehicle cameras, inparticular fisheye cameras, which each have a predefined field of view.7. The driver assistance system according to claim 6, wherein the dataprocessing unit is configured to calculate the concealed regionsdependent on the fields of view of the pertinent optical environmentsensors.
 8. The driver assistance system according to claim 1, whereinthe data processing unit is configured to calculate the concealedregions dependent on a relative speed between the detected obstacles andthe vehicle.
 9. A method of determining concealed regions in a vehicleenvironment of a vehicle, comprising the following steps: (a) evaluatingsensor data, which are generated by environment sensors includingoptical environment sensors of the vehicle, to detect obstacles in thevehicle environment; and (b) calculating, from the sensor data,dependent on the detected obstacles, concealed regions which areconcealed from a respective view of at least a respective one of theoptical environment sensors by the detected obstacles and restrict arespective field of view of the respective optical environment sensor,wherein the calculating of the concealed regions comprises respectivelydetermining, from the sensor data, at least one of a size, an extent anda contour of each respective one of the detected obstacles, and thencalculating each respective one of the concealed regions from therespective determined size, extent and/or contour of the respectivedetected obstacle that conceals the respective concealed region.
 10. Themethod according to claim 9, further comprising processing, inparticular filtering, the sensor data, which originate from the opticalenvironment sensors of the vehicle in the calculated concealed regions.11. The method according to claim 9, further comprising covering theconcealed regions with textured areas in the sensor data for beingdisplayed to a driver of the vehicle.
 12. The method according to claim9, wherein the concealed regions are calculated dependent on aprojection surface used for representing images by projecting the sensordata onto the projection surface.
 13. The method according to claim 9,wherein the optical environment sensors are mounted on the vehicle, andfurther comprising actuating the optical environment sensors, inparticular switching between different ones of the optical environmentsensors mounted on the vehicle, dependent on the concealed regions. 14.The method according to claim 9, wherein the concealed regions arecalculated dependent on predefined fields of view of the pertinentoptical environment sensors.
 15. The method according to claim 9,wherein the concealed regions are calculated dependent on a relativespeed between the detected obstacles and the vehicle.
 16. The methodaccording to claim 9, wherein the calculating of the concealed regionsfurther comprises defining a boundary of a respective one of theconcealed regions by a light beam that extends from an extreme outermostcontour point of a respective one of the detected obstacles to arespective one of the optical environment sensors.
 17. A method ofoperating a driver assistance system of a vehicle having a display, adata processor and sensors including a first optical sensor mounted onthe vehicle, wherein the method comprises the steps: a) with thesensors, sensing an environment outside of the vehicle and producingsensor data that represents features of the environment; b) with thedata processor, evaluating the sensor data, and from the sensor data,detecting an obstacle that exists in the environment, determining thatthe obstacle conceals, from the first optical sensor, a concealed regionin a field of view of the first optical sensor, determining at least oneof a size, an extent and a contour of the obstacle, and calculating theconcealed region from the determined size, extent and/or contour of theobstacle; c) with the data processor, further processing the sensor datato produce processed data dependent on and in response to the calculatedconcealed region; and d) on the display, displaying informationdetermined from the processed data, wherein the information is adaptedto assist a driver of the vehicle in performing a driving maneuver ofthe vehicle.
 18. The method according to claim 17, wherein the furtherprocessing comprises filtering the sensor data dependent on and inresponse to the calculated concealed region.
 19. The method according toclaim 17, wherein the further processing comprises covering thecalculated concealed region of the sensor data with a textured area tobe displayed in the information on the display.
 20. The method accordingto claim 17, wherein the sensors further include a second optical sensormounted on the vehicle, wherein the method further comprises, from thesensor data, determining whether any object in the environment concealsfrom the second optical sensor any concealed region in a field of viewof the second optical sensor, and calculating any such concealed regionin the field of view of the second optical sensor; and wherein thefurther processing of the sensor data comprises determining that anysuch concealed region in the field of view of the second optical sensoris less extensive in area or proportion than the concealed region in thefield of view of the first optical sensor, and switching from the sensordata produced by the first optical sensor to the sensor data produced bythe second optical sensor being included in the processed data.
 21. Themethod according to claim 17, wherein the calculating of the concealedregion is further dependent on a relative speed between the vehicle andthe obstacle.
 22. The method according to claim 17, further comprisingdetermining, from the processed data, a measure of a traffic density oftraffic on a road on which the vehicle is driving.